In order to determine the cost of each pencil we have to divide the total cost for the package of pencils by the number of pencils contained
For the 4 pencils box:
Cost per pencil = Total cost/number of pencils
Cost per pencil = 6/4 = 1.5
Similarly, for the 5 pencils package:
Cost per pencil = 7/5 = 1.4
As you can see, the $7 package is better to buy, because each pencil costs $1.4, then, option A is the correct answer